Bradley was arrested in July after police found a tractor-trailer near a Walmart in San Antonio and discovered 39 undocumented immigrants, eight of whom were already dead. Two more would die in the hospital.

The immigrants who survived told authorities that the trailer had contained as many as 200 people at one point during its journey from Mexico.

The gruesome discovery revealed a horrifying odyssey to the United States at a time when immigration arrests had spiked under President Trump and federal officials said illegal border crossings had plummeted. The case also highlighted the extreme dangers people face as they try to enter the country.

“Human smuggling is a horrendous crime, and unfortunately, it does not get a lot of media attention, until you have a tragic situation like this happen,” Jack Staton, acting assistant director of intelligence for ICE’s Homeland Security Investigations (HSI) arm, said at the time. Staton called human smuggling “100 percent [a] crime against humanity,” adding that “this is just victimizing people that are attempting to get a better life.”

Bradley initially told authorities that he was unaware there were people in the trailer, saying that when he stopped at Walmart for a bathroom break, he heard banging and shaking from the trailer and was “surprised” to find people packed inside upon opening the doors.

The truck had not been outside the store long: Surveillance video showed that it was parked at Walmart for just 30 minutes before a store worker encountered someone from the trailer asking for water, a company spokesman said.

Court documents paint a harrowing picture of the events that led to the deaths.

During the journey, the people packed into the sweltering tractor-trailer banged on the walls for help, asking for air. But the vehicle did not stop.

The refrigeration system did not work, and the vent holes were likely clogged, Bradley later told federal agents. The passengers took turns breathing through a hole in the side. Some passed out.

The passengers had been tagged with colored tape, allowing the smugglers to more easily sort them at the journey’s end — who would be handed off to which awaiting vehicle.

Some of the people packed into the trailer had traveled hundreds of miles from central Mexico.

A makeshift memorial in the San Antonio Walmart store parking lot. (Eric Gay/AP)

In addition to the 10 travelers who died, dozens of others were hospitalized, some with critical injuries. All the dead or injured were undocumented, federal authorities said. The group included four juveniles — all teenagers — who were unaccompanied by adults, the authorities said.

Some of the travelers had spent days held in a house near the U.S.-Mexico border, while others were told to pay thousands of dollars to a group linked to a deadly Mexican drug cartel for safe passage across the Rio Grande, The Post previously reported.

It is unclear what happened to the other travelers, though certain visas allow victims of some crimes to remain in the United States if they can help authorities investigate or prosecute crimes.

By pleading guilty, the U.S. attorney’s office said, Bradley “admitted that … he conspired to transport and did transport undocumented aliens in the United States for financial gain; to further their illegal entry into this country; with reckless disregard that they entered this country illegally; and, which resulted in the death of ten undocumented aliens.”

The admission of guilt “helps to close the door on one of the conspirators responsible for causing the tragic loss of life and wreaking havoc on those who survived this horrific incident,” Shane M. Folden, ICE-HSI special agent in charge, said in a statement.

Folden added that the incident is “a glaring reminder that alien smugglers are driven by greed and have little regard for the health and well-being of their human cargo, which can prove to be a deadly combination.”

Bradley’s co-defendant, a 47-year-old undocumented immigrant named Pedro Silva Segura, was indicted last month and charged with two counts of “transporting undocumented aliens resulting in serious bodily injury and placing lives in jeopardy,” and two counts of conspiracy.

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